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9#include <linux/sched/task_stack.h>
10#include <linux/sched/debug.h>
11#include <linux/sched.h>
12#include <linux/kernel.h>
13#include <linux/export.h>
14#include <linux/kallsyms.h>
15#include <linux/stacktrace.h>
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22
23void stack_trace_print(const unsigned long *entries, unsigned int nr_entries,
24 int spaces)
25{
26 unsigned int i;
27
28 if (WARN_ON(!entries))
29 return;
30
31 for (i = 0; i < nr_entries; i++)
32 printk("%*c%pS\n", 1 + spaces, ' ', (void *)entries[i]);
33}
34EXPORT_SYMBOL_GPL(stack_trace_print);
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45
46int stack_trace_snprint(char *buf, size_t size, const unsigned long *entries,
47 unsigned int nr_entries, int spaces)
48{
49 unsigned int generated, i, total = 0;
50
51 if (WARN_ON(!entries))
52 return 0;
53
54 for (i = 0; i < nr_entries && size; i++) {
55 generated = snprintf(buf, size, "%*c%pS\n", 1 + spaces, ' ',
56 (void *)entries[i]);
57
58 total += generated;
59 if (generated >= size) {
60 buf += size;
61 size = 0;
62 } else {
63 buf += generated;
64 size -= generated;
65 }
66 }
67
68 return total;
69}
70EXPORT_SYMBOL_GPL(stack_trace_snprint);
71
72#ifdef CONFIG_ARCH_STACKWALK
73
74struct stacktrace_cookie {
75 unsigned long *store;
76 unsigned int size;
77 unsigned int skip;
78 unsigned int len;
79};
80
81static bool stack_trace_consume_entry(void *cookie, unsigned long addr)
82{
83 struct stacktrace_cookie *c = cookie;
84
85 if (c->len >= c->size)
86 return false;
87
88 if (c->skip > 0) {
89 c->skip--;
90 return true;
91 }
92 c->store[c->len++] = addr;
93 return c->len < c->size;
94}
95
96static bool stack_trace_consume_entry_nosched(void *cookie, unsigned long addr)
97{
98 if (in_sched_functions(addr))
99 return true;
100 return stack_trace_consume_entry(cookie, addr);
101}
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111unsigned int stack_trace_save(unsigned long *store, unsigned int size,
112 unsigned int skipnr)
113{
114 stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
115 struct stacktrace_cookie c = {
116 .store = store,
117 .size = size,
118 .skip = skipnr + 1,
119 };
120
121 arch_stack_walk(consume_entry, &c, current, NULL);
122 return c.len;
123}
124EXPORT_SYMBOL_GPL(stack_trace_save);
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135unsigned int stack_trace_save_tsk(struct task_struct *tsk, unsigned long *store,
136 unsigned int size, unsigned int skipnr)
137{
138 stack_trace_consume_fn consume_entry = stack_trace_consume_entry_nosched;
139 struct stacktrace_cookie c = {
140 .store = store,
141 .size = size,
142
143 .skip = skipnr + (current == tsk),
144 };
145
146 if (!try_get_task_stack(tsk))
147 return 0;
148
149 arch_stack_walk(consume_entry, &c, tsk, NULL);
150 put_task_stack(tsk);
151 return c.len;
152}
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162
163unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
164 unsigned int size, unsigned int skipnr)
165{
166 stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
167 struct stacktrace_cookie c = {
168 .store = store,
169 .size = size,
170 .skip = skipnr,
171 };
172
173 arch_stack_walk(consume_entry, &c, current, regs);
174 return c.len;
175}
176
177#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
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189
190int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
191 unsigned int size)
192{
193 stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
194 struct stacktrace_cookie c = {
195 .store = store,
196 .size = size,
197 };
198 int ret;
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204 if (!try_get_task_stack(tsk))
205 return 0;
206
207 ret = arch_stack_walk_reliable(consume_entry, &c, tsk);
208 put_task_stack(tsk);
209 return ret ? ret : c.len;
210}
211#endif
212
213#ifdef CONFIG_USER_STACKTRACE_SUPPORT
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221unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
222{
223 stack_trace_consume_fn consume_entry = stack_trace_consume_entry;
224 struct stacktrace_cookie c = {
225 .store = store,
226 .size = size,
227 };
228 mm_segment_t fs;
229
230
231 if (current->flags & PF_KTHREAD)
232 return 0;
233
234 fs = force_uaccess_begin();
235 arch_stack_walk_user(consume_entry, &c, task_pt_regs(current));
236 force_uaccess_end(fs);
237
238 return c.len;
239}
240#endif
241
242#else
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248
249__weak void
250save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
251{
252 WARN_ONCE(1, KERN_INFO "save_stack_trace_tsk() not implemented yet.\n");
253}
254
255__weak void
256save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
257{
258 WARN_ONCE(1, KERN_INFO "save_stack_trace_regs() not implemented yet.\n");
259}
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269unsigned int stack_trace_save(unsigned long *store, unsigned int size,
270 unsigned int skipnr)
271{
272 struct stack_trace trace = {
273 .entries = store,
274 .max_entries = size,
275 .skip = skipnr + 1,
276 };
277
278 save_stack_trace(&trace);
279 return trace.nr_entries;
280}
281EXPORT_SYMBOL_GPL(stack_trace_save);
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292unsigned int stack_trace_save_tsk(struct task_struct *task,
293 unsigned long *store, unsigned int size,
294 unsigned int skipnr)
295{
296 struct stack_trace trace = {
297 .entries = store,
298 .max_entries = size,
299
300 .skip = skipnr + (current == task),
301 };
302
303 save_stack_trace_tsk(task, &trace);
304 return trace.nr_entries;
305}
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316unsigned int stack_trace_save_regs(struct pt_regs *regs, unsigned long *store,
317 unsigned int size, unsigned int skipnr)
318{
319 struct stack_trace trace = {
320 .entries = store,
321 .max_entries = size,
322 .skip = skipnr,
323 };
324
325 save_stack_trace_regs(regs, &trace);
326 return trace.nr_entries;
327}
328
329#ifdef CONFIG_HAVE_RELIABLE_STACKTRACE
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342int stack_trace_save_tsk_reliable(struct task_struct *tsk, unsigned long *store,
343 unsigned int size)
344{
345 struct stack_trace trace = {
346 .entries = store,
347 .max_entries = size,
348 };
349 int ret = save_stack_trace_tsk_reliable(tsk, &trace);
350
351 return ret ? ret : trace.nr_entries;
352}
353#endif
354
355#ifdef CONFIG_USER_STACKTRACE_SUPPORT
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363unsigned int stack_trace_save_user(unsigned long *store, unsigned int size)
364{
365 struct stack_trace trace = {
366 .entries = store,
367 .max_entries = size,
368 };
369
370 save_stack_trace_user(&trace);
371 return trace.nr_entries;
372}
373#endif
374
375#endif
376